FEEDBACK CONTROL FOR SCANNING TYPE TERNAL MICROSCOPE

摘要

PURPOSE: To improve the feedback control of a scanning tunnel microscope by generating with the third means control signals indicative of every vertical position of its chip in response to output signals from the second means and signals from the fourth means stored therein in advance. CONSTITUTION: A feedback loop not only utilizes local error signals or data indicative of every position of a chip 10, but also fetches stored information regarding the topography of every position of the chip 10 in order to vertically position the chip 10. The utilization of information from adjacent scanning lines 20 allows the feedback circuit to predict topography for its rapid operation as compared with the case where only local error information is utilized. The feedback control is thus correspondingly improved to have improved responsiveness.